If this was the General Election, what on earth will next year's Holyrood contest bring for Scottish Labour?

The sheer speed of the collapse has been stunning. It took fully five elections, 1979 to 1997, to reduce Scottish Tories from 22 seats to none at all. Labour had withered not in five years but in the interval between an autumn and an early summer's day. And this was supposed to be a party rooted in the culture, politics and collective memories of a country.

You can run through a few of the explanations offered. Campaigning alongside Conservatives in the referendum? The very nature of the referendum choice itself? The sense that Labour had been given their chance for many a long generation and failed? Those didn't help.

Or perhaps the estrangement began with Tony Blair, his "new" Labour, and his Iraq war? In reality, that's not what election numbers say. It would be wiser for the party to ask why Scots have been so deeply unimpressed by Ed Miliband, granting him "popularity" ratings that have seemed like calculated insults.

Perhaps the rot set in long before. But when exactly? Complacency, often mentioned, is not a new charge. It's an old story to tell of Labour in Scotland taking seats and voters for granted, "doing the business" with a nod and a wink, and treating a country's affairs as a job creation scheme.

Yet that would be the point: there's nothing new in the complaints. They are as traditional as Labour's dominance, as common as the charge that the party of Keir Hardie affects socialism only when it suits, that it lost its identity and soul long since. They don't explain why the roof fell in with such a crash.

We don't know exactly how bad the damage is. We do know that yesterday Labour people were behaving as though a handful of survivors would count as some sort of triumph. That won't help the party. This morning, it has an existential question to confront. If this was the General Election, what on earth will next year's Holyrood contest bring?

Labour in Scotland have been dodging a fundamental issue since they answered the demand for devolution. Who is they for? Whom do they represent? The mass flight of former voters since the referendum says all the glib talk about "hard-working families" is no answer. Trying to rebrand yourself as "proud patriotic Scots" misunderstands the questions.

The Scottish party faces in two directions, north and south, Scotland and Westminster. Loyalists might argue it can do no other and still remain a Labour party. To that, Scottish voters have said: "So be it". Either this is the time for a truly autonomous party in alliance with colleagues in England and Wales, or the time has gone.

This morning, the clock has stopped ticking. Labour have allowed Nicola Sturgeon and the Scottish National Party to represent a country and its hopes. Labour have been supplanted, in large part, because they have refused to believe that anyone else could do a job they treated as a hereditary position. They forgot about trust and faith and all the simple reasons why people give their votes.

The SNP have worked hard to replace Labour. For years they have had precious little luck, especially in the Central Belt. But even the Nationalists did not see this morning coming. They had the wit not to falter after their referendum defeat, and the human resources to punish opponents whose local organisations decayed long ago. The truth remains that Labour conceded the game.

The party did not understand that the referendum was a trap it could never escape. Campaigning alongside the Tories, in an effort backed by Tory funds, Tory media and the British state simply tightened the noose. How do you represent Scotland with those allies? By insisting that Scottish Conservatives are as Scottish as anyone? Very true. But now try that in the schemes.

Labour in Scotland have spent a long time despising the politics of identity. They are on their knees now, ironically, because of a crisis of identity. We have heard a lot lately about what Scotland means to Ed Miliband. It might have been better to ask what Mr Miliband ever meant to Scotland and why, suddenly, that mattered.

You do not catch history's stream with a few words. Giving your party leader the grisly Twitter handle @JimForScotland is symptomatic of a party's ills, not a cure. Labour in Scotland have won elections for decades by invoking old dreams, old loyalties, and football analogies. They have used nostalgia for working-class bonds as a campaign tool and missed something important. What if Scotland has changed?

This morning, we know that to be true. Labour, judging by their campaign here, have yet to realise that the country, its politics and those disputed "values" were not frozen in time when Margaret Thatcher found herself in Downing Street. Labour in Scotland went through the motions of refighting old battles for too long. Then they campaigned alongside the old, alleged enemy.

For a party once so dominant, the consequences are fearful. But there is something worse than the results. Those who inflicted them are the people who once made Labour Scotland's party. A rejection of that sort is absolute.